International patent application WO 2010/054852 A2 discloses a system for automatically docking a mobile machine to a movable supply. It is particularly suitable for automatically docking an RTG to a conductor rail serving as a movable supply. This system comprises a docking device having an advancer unit for advancing in a direction transversely to said conductor rail, by means of an extension arm. On the end portion with which the extension arm can be advanced to said conductor rail, a special carriage for connection to the conductor rail is provided. Said carriage holds the sliding contacts to be coupled in said conductor rail in the horizontal and vertical directions. Said carriage is guided and supported against supporting rails, which are additionally provided.
Patent application DE 10 2008 024 572 A1 describes a similar system, especially for docking an RTG to a conductor rail. A telescopic extension arm is suggested with this system, the arm being docked to the conductor rail using a special collector trolley. This collector trolley allows for play in the vertical direction as well as transversely to the mobile direction. This allows use of a trail with conductor rail, which is known as such, also in combination with a vehicle mobile on tires, in particular with an RTG.
A further system which similarly serves especially the power supply of an RTG by a conductor rail, is known from international patent application WO 2012/130630 A1. Compared to the system described in WO 2010/054852, this system is intended to remove the drawback of a complicated advancer device for advancing the current collector to said conductor rail. In addition to a transverse advancer unit comprising an extension arm extendable in the horizontal direction, that docking device includes a vertical advancer unit allowing the end portion of said extension arm to be advanced also in the vertical direction.
Automatic docking of a mobile machine to a moving supply for supplying electric current is desirable in many applications. The electrification of vehicles including a dedicated Diesel generator for supplying electric driving motors is particularly efficient and not harmful to the environment. This is mostly the case with stacker cranes of the RTG type for example. To reduce the consumption of Diesel fuel, electrification is also desirable for so-called pneumatic-tire van entrainment members, which in most cases can stack containers only in a row. RTGs and van entrainment members are employed in docks or other container handling sites. But electric current supply is also desirable in other fields, for example for a stacker/reclaimer in surface mining or underground mining.
Known solutions are mainly based on the principle of a conductor rail having a current collector as a movable supply. The sliding contacts on the conductor rail are inherently subject to considerable wear. Conductor rails are robust, but require frequent and elaborate maintenance. In addition, they are suitable for data signal transmission only to a limited extent, and they are not suitable for supplying different media such as gaseous or liquid operating media. For example, a solution that is based on a conductor rail cannot provide for a water supply of a sprinkling system of a stacker/reclaimer. Neither can vehicles equipped with pneumatic tires like RTGs be supplied by using a movable supply that is based on the principle of a conductor rail. Finally, conductor rails cannot be extended without considerable efforts and they are not suitable for modular use.
Another solution is known from patent application US 2012/043291 A1. The latter suggests, as an alternative to conductor rails, supplying an RTG with a cable reel or with an energy guiding chain. To respect a given travel direction a power supply truck that runs on rails (rail-bound) is provided in addition to the RTG, the truck including the cable reel or being connected to the energy guiding chain. In order not to impair the freedom of movement of the RTG, the power supply truck is connected to the RTG by way of a special mechanical docking device, that allows for significant play both vertical and in transverse direction. The connection of power supply between the power supply truck and the RTG is to be made manually.